Patients undergoing an elective coronary angiogram with mild kidney disease and currently taking an ACE inhibitor or ARB will be randomly divided into two groups. One group will continue taking their ACE inhibitor or ARB while the other group will stop taking their ACE inhibitor or ARB for at least 24 hours before and will resume their ACE inhibitor or ARB 48 to 96 hours after their angiogram. In both groups, kidney function will be assessed by means of a simple blood test both before and 48 to 96 hours after the angiogram. By doing this, we can determine which group had more kidney damage and which group had less kidney damage from the contrast exposure. We suspect that patients who do not take their ACE inhibitor around the time of their angiogram will have less kidney damage. All patients will receive the accepted measures for preventing kidney disease from contrast dye exposure.